Adding keyframes while modifiers are active
If you want to set keyframes, enable &quot;additive&quot; on the modifier settings of any channels you wish to keyframe, then keyframe them.  (This will require expanding the f-curve modifiers so you can see their options.)  If you'd like to disable &quot;additive&quot; afterwards, you can, and the keyframes will remain, but keep in mind that keyframes don't actually affect the output of modified f-curves unless &quot;additive&quot; is set-- otherwise, the modifier straight up replaces the keyframed values.